DTC:1415, 1416, and Auxillary temp is high

[IronDonkey]

I recently purchased a 2015 G21 PCM ZR409 (210 hours) and I am having a recurring problem with these codes showing up. I am new to Nautique's and looking for help. They will only pop if at higher RPM. Engine is never getting hot - typically running 168-174 F at all times regardless of RPM. If I cruise below 4000 RPM they won't ever come up, and we can surf all day. As soon as I speed up the error code will trigger within 5 minutes. Eventually DTC - 1418 will pop - stage 2 and boat will go into limp mode.

Impeller was replaced this winter, when oil change and transmission was changed as well. We have loaded the new software update from PCM onto motor recently as we thought maybe it was a faulty trigger point on a sensor or something.

Any help would be greatly appreciated.

[mlange]

For a 1415 from the PCM Service Manual...

Exhaust Manifold Water Temperature (EMWT) Sensor
• Check Condition - Engine Running
• Fault Condition - Exhaust Manifold Water Temperature reading or estimate greater than the stage 1 limit
when operating at a speed greater than defi ned in the diagnostic calibration
• Corrective Action(s) - Sound audible warning or illuminate secondary warning lamp, disable adaptive
learn fueling correction during active fault. Recommend a power derate 1/2 and/or a low rev limit to
protect engine from possible damage.
• Non-emissions related fault
The EMWT sensor is a thermistor (temperature sensitive resistor) located in the engine coolant. There is one
located in each CES exhaust manifold. The ECM provides a voltage divider circuit so that when the coolant
is cool, the signal reads higher voltage, and lower when warm.
This fault will help protect the engine in the event of over temperature. When the coolant exceeds x deg. F
and engine RPM exceeds y RPM for the latch time this fault will set.

Diagnostic Aids

□ If the “EMWT1 High Voltage” fault is also present, follow the troubleshooting procedures for that
fault as it may have caused “EMWT1 Sensor Higher Than Expected 1.”
□ Check that the heat exchanger has a proper amount of ethylene glycol/water and that the heat
exchanger is not leaking
□ Ensure that there is no trapped air in the cooling path
□ Inspect the cooling system for cracks and ensure connections are leak free
□ Check that the raw water pickup is not blocked/restricted by debris and that the hose is tightly
connected
□ Check that the thermostat is not stuck closed
□ Check that the raw water pump/impeller is tact and that it is not restricted
□ Verify that the proper amount of raw water fl ow is being achieved, both static and underway